BOSTON (AP) — Two college friends of suspected Boston Marathon bomber Dzhokhar Tsarnaev were indicted Thursday for allegedly trying to thwart investigators by throwing away fireworks and other items they found in Tsarnaev’s dorm room the day before his capture.

Authorities later discovered the fireworks in a New Bedford landfill, the federal indictment says.

Dias Kadyrbayev and Azamat Tazhayakov, both 19 and nationals of Kazakhstan, face charges of conspiracy to obstruct justice. The two, who were in the U.S. attending college and shared an apartment in New Bedford, have been detained since they were charged in a criminal complaint in May.

If convicted, they face up to 20 years in prison. Both are scheduled for arraignment Tuesday.

Tazhayakov’s attorney, Arkady Bukh, said his client did nothing wrong and he’s tried for months to convince authorities to drop the case.

“For me, this sounds like a witch hunt,” he said. “And this is the same view (my) client has.”

Kadyrbayev’s attorney, Robert Stahl, said his client never knowingly took evidence from Tsarnaev’s dorm room.

“My young client ... was shocked and horrified to learn that someone he knew was involved in the terrible Marathon bombing,” he said.

Tsarnaev, 20, is accused in the April 15 blasts at the Boston Marathon that killed three people and injured more than 260. He was captured April 19 in the Boston suburb of Watertown, after he was found hiding in a drydocked boat, hours after a shootout with police. He’s pleaded not guilty.

Also Thursday, a hearing scheduled for Monday for a third Tsarnaev friend charged in the case was canceled. Robel Phillipos is accused of lying to investigators about visiting Tsarnaev’s dorm room. In court documents, his attorneys say they’re in talks that could resolve the case.

Tsarnaev, Kadyrbayev, Tazhayakov and Phillipos were all students at the University of Massachusetts at Dartmouth.

On April 18, FBI investigators working the bombing posted pictures of Tsarnaev and his brother Tamerlan Tsarnaev, an alleged co-conspirator who died during the manhunt for the suspects.

According to the indictment, that day Kadyrbayev received a text message from Dzhokhar Tsarnaev suggesting that, if he wanted, he could go to Tsarnaev’s “and take what’s there.”

The indictment alleges that Kadyrbayev and Tazhayakov removed several items from the room that evening, including Tsarnaev’s laptop computer and a backpack containing fireworks, which were opened so their explosive powder could be seen. They also found a jar of petroleum jelly, which Kadyrbayev told Tazhayakov he believed Tsarnaev used to make bombs, the indictment said.

The indictment says that night, after Tazhayakov agreed, Kadyrbayev put the backpack with the fireworks and jelly in a garbage bag, and tossed the bag in a trash bin outside the apartment.

The next morning, after Tsarnaev had been identified as a bombing suspect in multiple news reports, they allegedly watched as a garbage truck emptied the bin.

But Bukh said his client never agreed to anything regarding disposal of the fireworks and backpack. And Stahl said Kadyrbayev fully cooperated with the FBI, including by turning over Tsarnaev’s laptop and telling them where they could find the backpack.

“Despite the rush to judgment and, now, the present charges, Dias trusts the American justice system and looks forward to proving his innocence at trial,” Stahl said.